Publication Type

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Journals and Conferences

Key Phrases

This is a review of models of inflation and of their predictions for the primordial non–Gaussianity in the density perturbations which are thought to be at the origin of structures in the Universe. Non–Gaussianity emerges as a key observable to discriminate among competing scenarios for the generation of cosmological perturbations and is one of the primary… (More)

We provide an analytical approach to the second–order Cosmic Microwave Background (CMB) anisotropies generated by the non–linear dynamics taking place at last scattering. We study the acoustic oscillations of the photon–baryon fluid in the tight coupling limit and we extend at second– order the Meszaros effect. We allow for a generic set of initial… (More)

Scalar fields with inverse power-law effective potentials may provide a negative pressure component to the energy density of the universe today, as required by cosmological observations. In order to be cosmologically relevant today, the scalar field should have a mass mφ = O(10 −33eV), thus potentially inducing sizable violations of the equivalence… (More)

We provide the gauge-invariant expression for large-scale cosmic microwave background temperature fluctuations at second-order perturbation theory. This enables us to define unambiguously the nonlinearity parameter f(NL), which is used by experimental collaborations to pin down the level of non-Gaussianity in the temperature fluctuations. Furthermore, it… (More)

Correlated adiabatic and isocurvature perturbation modes are produced during inflation through an oscillation mechanism when extra scalar degrees of freedom -other than the inflaton field are present. We show that this correlation generically leads to sizeable non-Gaussian features both in the adiabatic and isocurvature perturbations. The nonGaussianity is… (More)

We compute the fully non-linear Cosmic Microwave Background (CMB) anisotropies on scales larger than the horizon at last-scattering in terms of only the curvature perturbation, providing a generalization of the linear Sachs-Wolfe effect at any order in perturbation theory. We show how to compute the n-point connected correlation functions of the large-scale… (More)

We discuss how primordial (e.g. inflationary) non-Gaussianity in the cosmological perturbations is left imprinted in the Large-Scale Structure of the universe. Our findings show that the information on the primordial non-Gaussianity set on super-Hubble scales flows into Post-Newtonian terms, leaving an observable imprint in the Large-Scale Structure. Future… (More)

Various data analyses of the Cosmic Microwave Background (CMB) provide observational hints of statistical isotropy breaking. Some of these features can be studied within the framework of primordial vector fields in inflationary theories which generally display some level of statistical anisotropy both in the power spectrum and in higher-order correlation… (More)

The primary interest in inflation [1,2] is as a mechanism to explain the origin of structure in the Universe from vacuum fluctuations in an early inflationary era which are swept up to arbitrarily large scales. The simplest inflationary models predict an almost scaleinvariant spectrum of Gaussian, adiabatic density perturbations. Such a spectrum was already… (More)